In a conventional solid electrolytic capacitor having a built-in fuse, the fuse is positioned by being once extended upward from a cathode terminal wall of a capacitor element to form a loop and connected to an external lead ( or wire) situated adjacent a central portion of the capacitor element. This results in a limitation in decreasing the size of a resin package of the capacitor. In an attempt to decrease the package size, a capacitor structure as shown in FIG. 3 has been proposed.
In FIG. 3, an internal anode lead 22 projecting from one lateral surface of a capacitor element 21 is connected at its end to an external lead 23; a fuse-supporting plate 25 is connected at its one end to a cathode terminal wall 24, or an outer wall of the capacitor element 21; a fuse 26 is electrically connected between the other end of the fuse-supporting plate 25 and an external lead 27; and the capacitor element 21 together with a portion of each of the external leads 23 and 27 is encapsulated with a resin package 28 by molding. As shown in perspective at FIG. 4, the fuse-supporting plate 25 and the external lead 27 are disposed offset to each other in plan so as to allow easy connection therebetween through the fuse 26.
In this proposed solid electrolytic capacitor, however, distance A (refer to FIG. 3) between the cathode terminal wall 24 to which the fuse 26 is pressure-welded and the outer wall of the resin mold package 28 is only about 0.3 mm even terms of design center value. This causes a problem that disposing the fuse-supporting plate 25 and fuse 26 within distance A will result in exposure of the fuse 26 from the resin package or in a like fault. The fuse-supporting plate 25 is about 1 mm thick on the average and the fuse 26 is 0.1 to 0.12 mm in diameter. Accordingly, an extent of about 0.2 to 0.22 mm of distance A (about 0.3 mm) is occupied only by the two components.
Further, distance A is so small that it becomes a bottleneck in increasing the size of the capacitor element 21 and, hence, a solid electrolyte capacitor of larger capacitance is difficult to realize.